In recent years, silicon photonics has been received a great deal of attention. Silicon photonics is a technology for reducing power consumption and increasing signal processing speed by integrating a light-emitting element using silicon, a silicon waveguide, and the like between chips in an LSI or inside a chip. As a result, there is a need for light-emitting elements using silicon that is inexpensive and small in environmental load as silicon photonics light sources. Moreover, since light with an energy lower than the band gap (approximately 1.125 eV at room temperature) of silicon (light with a wavelength of approximately 1100 nm or more) is easily transmitted through the silicon waveguide, light-emitting elements that emit such light have been demanded. Examples of light-emitting elements using silicon have been disclosed in Patent Literature 1 and Patent Literature 2. The silicon light-emitting diodes disclosed in Patent Literature 1 and Patent Literature 2 both have pn-junctions with thicknesses of 10 nm or less on their SOI substrates. These silicon light-emitting diodes disclosed in Patent Literature 1 and Patent Literature 2 emit light (wavelength of approximately 770 nm to 1000 nm) with an energy higher than the band gap of silicon. This is considered to be due to the quantum confinement effect caused by thinning the pn-junctions.
Citation List
Patent Literature
Patent Literature 1: Japanese Patent Laid-Open No. 2007-294628    Patent Literature 2: Japanese Patent Laid-Open No. H08-46237